Fire officials said Monday night that crews had made good progress battling a raging wildfire in the Sequoia National Forest, announcing that the blaze was 50% contained and that evacuations had been lifted.

Firefighters on the ground and in the air were able to make significant gains along the perimeter of the blaze, widening containment lines and using water to keep flareups in check, the U.S. Forest Service said.

The blaze had scorched about 2,600 acres of timber and grass since breaking out Saturday in Kern County west of Lake Isabella.

APphoto_Kern County Fire

Casey Christie / Associated Press

This jet powered DC-10 air tanker makes a long drop of fire retardant on the Shirley Fire on Saturday.

This jet powered DC-10 air tanker makes a long drop of fire retardant on the Shirley Fire on Saturday. (Casey Christie / Associated Press)

Earlier Monday, fire officials said that 1,000 homes were threatened. But an aggressive air attack, coupled with more than 1,000 firefighters on the ground, was able to help stem the tide, according to the Forest Service.

"For the first time since the start of the incident," fire officials said in a statement, "the fire did not burn actively in the afternoon."

The cause of the blaze was under investigation.

Fire officials said that helicopters were ready to attack the blaze Monday night if flames jumped the containment lines.

Fire officials said Monday that the cost of fighting the fire was about $6.2 million.